1. Field of the Invention
The invention relates to a method and apparatus for filling a line of moving containers with liquid and particularly to a method and apparatus for filling continuously moving containers from a continuously flowing source to a common predetermined level while avoiding spillage of the liquid onto the exterior surfaces of the containers.
2. Description of the Prior Art
U.S. Pat. No. 4,103,720, issued to the present applicant on Aug. 1, 1978, describes a method and apparatus for filling open-top containers with liquid material. The containers are advanced continuously in a line along a predetermined path through a filling region where liquid material is discharged from a reservoir in a continuous sheet over an inclined plate, the lower edge of which extends in the direction of advance above the open tops of the line of containers. In the filling region, the containers are tilted transversely to the path at a predetermined angle with respect to the vertical, and the flow rate of the liquid is adjusted so that each container is overfilled as it passes through the filling region.
To prevent the liquid stream from contacting the external surface of the containers, thus avoiding an extra cleanup step after filling, streams of air are directed towards the tilted containers transversely to the line of advance below their tops, so that the air passes around the peripheries of the containers adjacent to their tops. The air flow laterally deflects any part of the sheet of liquid which would otherwise flow between adjacent containers and also deflects the liquid overflowing from the lower part of the open top of each tilted container away from the side of the container. The deflected liquid falls into a trough below the line of containers and is recirculated from the trough back to the reservoir.
The apparatus of the applicant's U.S. Pat. No. 4,103,720 requires a relatively high volume flow from a source of compressed air for deflecting the liquid flow away from the exterior surfaces of the containers. Such a source is not always available.
Other systems are known which mechanically deflect fluent materials being discharged from a fixed spout into a line of continuously moving receptacles to prevent material falling between adjacent receptacles. For example, U.S. Pat. No. 2,785,707 to J. F. Ryan, Jr. et al. discloses apparatus for filling containers such as flanged cans or jars moving in a line under a spout continuously discharging a stream of liqui-form product. A cam-driven, pivotally mounted wedge-shaped deflector oscillates under the spout in synchronism with the movement of the containers. In its forward direction of movement it covers the gap between adjacent containers when the gap moves under the stream of material. The drive cam has a quick-return sector which then sends the deflector back through the stream to be in position to cover the succeeding gap as it arrives underneath the spout.
In U.S. Pat. No. 3,228,434 of K. R. Johnson et al. fluent materials are discharged continuously from a spout into a line of moving receptacles through rectangular funnels mounted on an elongated endless carrier which moves in synchronism with the receptacles. Johnson et al, also use a wedge-shaped deflector to cover the gap between adjacent funnels as the gap passes underneath the spout, but instead of a single oscillator, they provide individual dividers mounted between adjacent funnels in a manner to accommodate relative movement of the latter as the funnels pass around the arcuate end portions of the carrier path.
U.S. Pat. No. 3,369,577 discloses similar filling apparatus except that a number of deflectors or dividers are equally spaced around the periphery of a separate rigid support member which is mounted for rotation about a vertical axis. The circumferential spacing of the dividers is equal to the distance between corresponding parts of adjacent funnels, and the divider support rotates in synchronism with the funnel carrier, so that as successive dividers pass under the spout they are positioned directly above the gap between adjacent funnels.
Another example of filling apparatus which uses moving funnels to distribute fluent material into a line of moving receptacles is shown in U.S. Pat. No. 2,951,514 of W. E. Flack. In the Flack apparatus granular material flows over an inclined plate, the lower edge of which is positioned over a rotatable circular trough. The bottom of the trough is subdivided circumferentially into corresponding receptacles, the funnels and receptacles moving in a circular path under the edge of the inclined plate.
Further examples of filling apparatus of this general class are disclosed in U.S. Pat. Nos. 3,152,622 of O. Rothermel; 3,057,382 of D. B. Baker; 3,087,652 of H. L. Smith, Jr.; 4,010,594 of J. L. Boyd et al.; and 2,058,976 of H. E. Gray.
Except for the applicant's U.S. Pat. No. 4,103,720 and the Ryan U.S. Pat. No. 2,785,707, all of the above-mentioned patents are concerned with filling containers with dry products. Preventing contact by a flowing liquid product with the outer surfaces of the containers presents greater problems because of the tendency of liquid to splash, particularly at high flow velocities. Thus, the spout-type filling machines, which have a fixed discharge cross section, are not well suited for machines intended to deliver a wide range of filling rates to containers of different sizes.
Liquid products, particularly liquid food products, also present a more difficult clean up problem; so it is desirable to minimize the number and complexity of parts which convey the liquid product to the final containers.